1. Technical Field
The present disclosure relates to a warehouse that is capable of altering and/or holding steady the temperature of a quantity of product housed in cases forming pallet assemblies and storing such product, e.g., bulk foods. More particularly, the present disclosure relates to spacing, stacking and heat transfer structures used in such a warehouse.
2. Description of the Related Art
Freezer warehouses are known in which large pallets of items including meats, fruit, vegetables, prepared foods, and the like are frozen in blast rooms of a warehouse and then are moved to a storage part of the warehouse to be maintained at a frozen temperature until their removal.
U.S. patent application Ser. No. 12/877,392 entitled “Rack-Aisle Freezing System for Palletized Product”, filed on Sep. 8, 2010, the entire disclosure of which is hereby explicitly incorporated by reference herein, relates to an improved system for freezing food products. Shown in FIG. 1 is a large warehouse 2 that can be used to freeze and maintain perishable foods or like products. Large pallets of items, including meats, fruits, vegetables, prepared foods, and the like, are sent to warehouse 2 to be frozen employing a system whereby the palletized foods are frozen on storage racks.
FIG. 2 shows a top view of the interior of warehouse 2, in which rows of palletized product are shown such that pallet assemblies 52a abut chamber 6. As shown in FIG. 3, rows of racking 14 (see also FIG. 8) are positioned between aisles 10 and chambers 6. Each chamber 6 is enclosed by a pair of end walls 15 and top panel 17. Spacers 20 (FIGS. 5-7) separate respective rows of cases 22 to create a palletized product stack in the form of pallet assembly 52a which can be disposed and sealed against the exterior of racking 14 (FIG. 3) via forklifts 18 (see, e.g., FIGS. 3 and 4).
Air handlers 8, e.g., chillers (FIG. 2) provided in the interior of warehouse 2 produce conditioned, e.g., cold air and maintain the temperature of ambient air within the warehouse space at a desired temperature, e.g., +55° F. to −30° F. While warehouse 2 could be utilized to either freeze or thaw a quantity of product housed in cases contained on pallet assemblies 52a, the remaining description will use the example of a warehouse freezer, it being understood that similar arrangements and principles will be applied to a warehouse utilized to thaw product, with the air handler comprising a heater as opposed to a chiller.
Adjacent pairs of racking structures 14 (FIGS. 2-4) define a plurality of adjacent airflow chambers 6 (FIGS. 2 and 4) having air intake openings on opposite sides thereof and a plurality of air outlets having air moving devices, such as exhaust fans 12, on top panels 17, which cause freezing air to be drawn into chambers 6 through the air intake openings in racking 14 and to then exhaust into the warehouse space. The plurality of airflow chambers 6 are each defined by a pair of end walls 15 and top wall 17 having one or more air outlets and exhaust fans 12 associated therewith (FIG. 3). Pallet assemblies 52a (FIG. 5) are pressed against the intake openings in racking 14 such that a seal is formed between the pallets and the intake openings via side periphery seals, a bottom periphery seal, and a top periphery seal. The seals together define each respective intake opening. Freezing air is drawn through air pathways 16 (FIGS. 2, 4, and 5) within the palletized product in a direction towards chamber 6 to thereby quickly freeze the product. As shown in FIG. 5, spacers 20 may be placed between rows of cases 22 of product in an attempt to provide air pathways 24 through which airflow can enter chamber 6.
U.S. patent application Ser. No. 13/074,098 entitled “Swing Seal for a Rack-Aisle Freezing and Chilling System”, filed on Mar. 29, 2011, the entire disclosure of which is hereby explicitly incorporated by reference herein, discloses a top periphery seal useable to seal an intake opening as described above and which automatically adjusts to the height of pallet assembly 52a as illustrated in FIG. 6. As illustrated in FIG. 6, pallet assembly 52a (comprised of a plurality of cases 22 stacked on spacers 20 and pallet 4) can be positioned along pallet guide 56 and pressed against intake opening 54 such that a seal is formed between pallet assembly 52a and intake opening 54 via side periphery seals, a bottom periphery seal and an automatically adjustable top periphery seal surrounding intake opening 54. With such a construction, chilling or freezing air is drawn through air pathways 16 formed through pallet assembly 52a, as illustrated in FIGS. 2, 4 and 5.
FIG. 5 illustrates predicate spacer 20 which is formed in an undulating “egg carton” configuration. As illustrated in FIG. 7, individual cases 22 can crush under the weight of the product contained therein and the product contained in cases stacked directly above to cause overlap of cases 22 with a spacer 20 and prohibit airflow between product cases 22 positioned on opposite sides of the obstructed spacer 20. Undulating spacers 20 are particularly susceptible to obstruction due to drooping or sagging cases 22 due to the inconsistent support structure caused by the “hill and valley” configuration of such spacers. FIG. 7 illustrates case crushing and drooping at various sides and levels of pallet assembly 52a; however, this phenomenon is, in practice, more prevalently seen with respect to the spacers 20 separating lower rows of cases 22, as the bottom of pallet assembly 52a contains the heaviest cumulative load of cases 22 stacked thereon.
In the above described installation, utilizing “egg carton” spacers 20, heat transfer from chilled ambient air in warehouse 2 to the products contained in cases 22 is effected through forced convection which is facilitated by the irregular shape of egg carton spacers 20 to allow airflow in all directions through pallet assembly 52a. Alternative spacers such as wood slat spacers may also be utilized to separate cases 22 on pallet 4; however, spacers employed in warehouse installations utilized to keep the quantity of product at a desired temperature through forced convection are designed to allow for airflow in all directions. Because air can flow in all directions through predicate spacers 20 described above, thorough cooling or thawing of a product may not be achieved, as air entering between adjacent rows of product cases may exit pallet assembly 52a before encountering all of the cases of the row in question. Further, crushing and/or drooping of cases 22 may restrict airflow, as described above.
Another mechanism of heat transfer, i.e., conduction, can also be utilized to transfer heat to or from product. Predicate spacers 20 described above are made either of wood or plastic, which is not sufficiently thermally conductive to effect heat transfer via conduction. Therefore, in installations utilizing such spacers, heat transfer is effected solely by the use of forced convection.